Integrated circuits, such as microprocessors and memory devices, include many metal-oxide-semiconductor field-effect transistors (MOSFETs), which provide the basic switching functions to implement logic gates, data storage, power switching, and the like. In one application, MOSFETs have been widely employed in Switching Mode Power Supplies (SMPS) because they are power efficient and thermally efficient. In addition to MOSFET switches, a SMPS also comprises energy saving devices, such as inductors or capacitors.
A power supply is a key element in any electronic device and its performance can affect power efficiency, product safety and product performance. Thus, it is necessary for a power supply (e.g., an SMPS) to include a power monitoring system to monitor and/or regulate its output. Power regulation usually includes output voltage or current feedback. Since many SMPS systems (i.e., SMPS including power monitoring or regulation features) use current mode regulation, it is a critical for such systems to obtain accurate current information.
Recent computing applications demand SMPS systems to run at higher frequency to increase bandwidth. These applications also require SMPS systems to have a smaller form factor and reduced cost. SMPS systems manufacturers have responded to these requirements by using small inductors and capacitors. In addition, there is a trending to lower the operating voltage for SMPS systems (e.g., step-down DC-DC converters) so as to achieve higher speed operation and better power savings. As such, the voltage ratio (VIN/VOUT) between the input voltage and output voltage increases and the energy saving period (i.e. on-time duty D) becomes shorter. It is a challenge in such systems to accurately sense current information due to the high switching frequency, the short on-time duty and the noise made from switches turning-on and off.
It is within this context that aspects of the present disclosure arise.